This invention relates generally to fluid filtering devices and deals more particularly with a wash filter for bleeding a portion of the fluid flowing in a passageway through a filter plug mounted coaxially therein.
Wash filters of the prior art have had a wall-mounted screen or filter element over which a moving stream of fluid passes in a continuous washing or cleaning action and through which a portion of the moving stream is tapped and filtered. The use of fluid accelerating plugs in such filters is well known. Such plugs are impervious, bullet shaped deflectors, or abutments so arranged adjacent the screen to increase the flow velocity and washing action. The theory of operation for such wash filters is that at high velocity only the fluid itself is able to make the relatively sharp turn, or turns, required for entry into the wall-mounted screen, and foreign particles entrained in the fluid are carried downstream of the screen by reason of their greater momentum. Difficulties have been encountered, however, because the plug deflects entrained particles into the filter screen and the deflected fluid flow tends to drive the particles further into the screen. The washing action is correspondingly depreciated together with the filtering action.
It is, accordingly, a general object of the present invention to disclose an improved wash filter overcoming the above described deficiency of the prior art.